1. Field of the Invention
The present invention relates to an ink jet recording head which jets ink droplets onto a recording medium to form an image, a manufacturing method of the ink jet recording head, and an ink jet recording device.
2. Description of the Related Art
In recent years, ink jet recording devices have received attention as inexpensive color recording devices able to produce high quality images. As ink jet recording heads for the ink jet recording devices, there are known, for example, a piezoelectric ink jet recording head which jets ink from nozzles by the pressure generated by mechanically deforming a pressure chamber using a piezoelectric material, and a thermal ink jet recording head which energizes a heating element displaced in the individual channels, and then jets ink from nozzles by the pressure generated by the vaporized ink.
In the aforementioned thermal ink jet recording head, the temperature of the ink is raised above the temperature set by the heating element by heat generated at the time the ink is jetted. Thus, a problem arises in that this further increase in the ink temperature changes the viscosity of the ink and therefore the printing characteristics. Because of this problem, heat dissipation is ensured by structuring the ink jet recording head such that a heat sink, which is plate-shaped and has high heat conductivity, is joined to a lower surface of a head chip in which nozzles are formed.
A manufacturing method of such an ink jet recording head will be described briefly with reference to FIGS. 17A to 17D.
First, a flexible printed wiring board 202 is joined onto a heat sink 200 (see FIG. 17A). Next, a head chip 204 having nozzles for jetting ink formed therein is joined onto the heat sink 200 (see FIG. 17B). Subsequently, connecting terminals 205 formed at end portions of the head chip 204 in a longitudinal direction thereof (i.e., in a direction in which the nozzles are aligned) are connected to terminals of the flexible printed wiring board 202 by wire bonding (FIG. 17C). The head chip 204 and the heat sink 200 are interposed between a pair of members forming an ink supply structure 206 which supplies ink to the head chip 204. The head chip 204 and the heat sink 200 are fixed to the ink supply structure 206 by screws 210 inserted into holes 208 of the heat sink 200 (FIG. 17D).
The ink jet recording head 211 having a heat sink is manufactured in the above-described manner. However, in addition to devising still further improvements in printing performance and manufacturing efficiency, the following tasks remain.
When an attempt is made to make an ink jet recording device (or a recording head) compact, the heat sink and the flexible printed wiring board, which are not components essential for jetting ink, need to be removed or made compact.
However, as described above, the heat sink serves to control the temperature of ink (i.e., ink jetting performance). Therefore, in place of the heat sink, a structure which is simple and serves to control the ink temperature (i.e., suppress a further increase in the ink temperature) is necessary.
Further, in order to ensure ink sealing ability, the heat sink 200 of an ink jet recording device shown in FIG. 18 is fixed to the ink supply structure 206 by the screws 210. The screws 210 are inserted into the holes 208 on both sides of the heat sink 200 where the head chip 204 for jetting ink droplets is connected. Accordingly, pairs of conveying rollers 212 and 214, which are disposed at the upstream and downstream sides, respectively, of the ink supply structure 206 in a direction in which paper is conveyed, are arranged to be spaced from the head chip 204 (i.e., printing area) by a distance corresponding to the diameter of the screw 210. In this case, however, printing performance may deteriorate due to, for example, a distortion of the back end of paper passing through the pair of conveying rollers 212. This may be particularly problematic when further high image quality is desired.
Furthermore, when an attempt is made to make the head chip 204 compact, the standardized size of a head portion of the screw 210 becomes large relative to the size of the head chip 204. Therefore, the head portion of the screw 210 is located at a position protruding further toward a position A at which paper is conveyed than a nozzle end face of the head chip 204 (FIGS. 19A and 19B). With this structure, the distance between the nozzles of the head chip 204 and the paper conveying position A is too large, and therefore, inadequate printing, such as no ink droplets reaching the paper, may be caused. Moreover, this structure also has a problem in that a sliding member for removing solidified ink, dust, and the like adhered on the nozzle end face of the head chip 204 cannot be slid along the head chip 204 because of the protruding screws 210.
A thermosetting resin adhesive is used to join members forming the ink jet recording head, for example, the heat sink and the head chip, to each other. In this case, a problem arises in that time is necessary for curing and for cooling after curing, thereby decreasing manufacturing efficiency. Accordingly, there has been a demand for eliminating a curing (adhering) step from the manufacturing process of the ink jet recording head.
In order to solve the above-described problems, the present invention provides an ink jet recording head which improves printing performance and simplifies manufacture, a manufacturing method of the ink jet recording head, and an ink jet recording device.
In accordance with an aspect of the present invention, there is provided an ink jet recording head comprising: a plurality of nozzles for jetting ink; a plurality of separate channels each corresponding to one of the plurality of nozzles; a plurality of common liquid chambers each communicating with one or more of the plurality of separate channels; and a plurality of ink supply chambers each communicating with one of the plurality of common liquid chambers, wherein the respective common liquid chambers open towards a direction in which the separate channels extend, and open towards a direction substantially perpendicular to the direction in which the separate channels extend so as to communicate with the corresponding ink supply chambers.
In accordance with another aspect of the present invention, there is provided a heatsinkless recording head having substantially no heat sink, the recording head comprising: a head chip formed by laminated substrates; an ink manifold having an opening for accommodating the head chip; and an elastic sealing element interposed between the head chip and the ink manifold when the head chip is accommodated in the ink manifold.
In accordance with yet another aspect of the present invention, there is provided a manufacturing method of an ink jet recording head, the method comprising the steps of: providing a head chip which includes a plurality of nozzles for jetting ink, a plurality of separate channels each corresponding to one of the plurality of nozzles, and a plurality of common liquid chambers each communicating with one or more of the plurality of separate channels; providing an ink manifold which includes a plurality of ink supply chambers each communicating with one of the common liquid chambers; and assembling the head chip and the ink manifold in such a way that the respective common liquid chambers open towards a direction in which the separate channels extend, and open towards a direction substantially perpendicular to the direction in which the separate channels extend so as to communicate with the corresponding ink supply chambers.
In accordance with a further aspect of the present invention, there is provided an ink jet recording device, comprising: (a) an ink jet recording head including: a plurality of nozzles for jetting ink; a plurality of separate channels each corresponding to one of the plurality of nozzles; a plurality of common liquid chambers each communicating with one or more of the plurality of separate channels; and a plurality of ink supply chambers each communicating with one of the plurality of common liquid chambers, wherein the respective common liquid chambers open towards a direction in which the separate channels extend, and open towards a direction substantially perpendicular to the direction in which the separate channels extend so as to communicate with the corresponding ink supply chambers; (b) an ink cartridge mounted at the ink jet recording head; and (c) a drive unit for moving the ink jet recording head and the ink cartridge in a scanning direction substantially perpendicular to a direction in which paper is conveyed.
In accordance with a still further aspect of the present invention, there is provided an ink jet recording device, comprising: (a) a heatsinkless ink jet recording head having substantially no heat sink, including: a head chip formed by laminated substrates; an ink manifold having an opening for accommodating the head chip; and an elastic sealing element interposed between the head chip and the ink manifold when the head chip is accommodated in the ink manifold; (b) an ink cartridge mounted at the ink jet recording head; and (c) a drive unit for moving the ink jet recording head and the ink cartridge in a scanning direction substantially perpendicular to a direction in which paper is conveyed.